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International audience; Skutterudite CoSb3 material exhibits excellent thermoelectric properties for thermoelectric application. In this work, CoSb3 thin films were fabricated by direct current magnetron co-sputtering. The composition of thin films was controlled by regulating the deposition power of both Co and Sb. Then the as-deposited Sb-excess sample was chosen to process post-annealing. High-resolution transmission electron microscopy and X-ray diffraction, together with Raman analysis, demonstrate that the annealed samples have well-crystallized and nano-sized skutterudite CoSb3 structure. Hall measurement shows that specimens are P-type semiconductor. Both of the increasing of Seebeck coefficient and electric conductivity can be obtained when the samples annealed at appropriate temperature, indicating that thermally can improve its thermoelectric properties due to well-crystallized and nano-sized structure. © 2017 Elsevier B.V.

Titanium niobium mixed oxide films have been deposited by reactive magnetron serial co-sputtering. After post annealing at 650 °C in air, a monoclinic TiNb 2 O 7 phase was achieved. Lithium intercalation properties were determined and cathodic switching behavior has been demonstrated for this material. Maximum switching of the integral visual transmittance of 16.8% has been determined for this sample with a thickness of 156 nm.

In the present work, coatings in the material systems B-C-W and B-C-Ti have been synthesized by pulse magnetron sputtering, to exploit their potential as coatings for hard, wear resistant applications. These layers offer interesting properties, because of the possible amounts of carbides and borides that can form in the non-equilibrium deposition processes. Especially the amount of tungsten in the layers promises high wear resistance and corrosion protection at elevated temperatures. The B-C-W and B-C-Ti thin films have been deposited by pulsed magnetron co-sputtering in bipolar mode, using a boron carbide (B 4 C) target and a metal target (W or Ti) with a maximum total power input of 12.9 W/cm 2 . The amount of metal in the layers has been varied by adjusting the sputtering pulse length of the respective target material. The influence of bias voltage on the properties of B-C-W coatings has been investigated and it was found out that bias voltages of − 60 V … − 100 V lower the hardness of the coatings. The hardness and the Young's modulus of the layers have been determined by nanoindentation. Whereas the majority of coatings exhibits hardness around 20 GPa or lower, maximum hardness of 28 GPa and Young's modulus of 420 GPa are observed in a certain compositional range, in which coatings also distinguish by good thermal stability. Their composition has been analysed by using optical glow discharge emission spectroscopy (GD-OES) and Rutherford backscattering spectrometry (RBS).

ZnO p-type thin films were deposited by dual acceptor co-doping using nitrogen and silver via DC reactive magnetron co-sputtering. As precursor material were used a Zn and an Ag metallic targets with a purity of 99.99%. X-ray energy dispersive spectroscopy (EDX) confirmed the presence of Ag and N in ZnO: Ag,N films. The electrical properties were explored by Hall Effect measurement and showed a low hole concentration for the as-deposited ZnO: Ag,N film. However, after annealing treatment, the films remained p-type and the electrical properties were improved significantly. The best electrical properties showed a low resistivity of 8.56×10 Ωcm, Hall mobility of 23 cm/Vs and a very high hole concentration of 3.17×10 cm., This work was partially supported by Project CONACyT-105723.

Magneto-optic (MO) garnets are used in a range of applications in nanophotonics, integrated optics, communications and imaging. Bi-substituted iron garnets of different compositions are the most useful class of materials in applied magneto- optics due to their excellent MO properties (large Faraday effect) and record-high MO figure of merit among all semi- transparent dielectrics. It is highly desirable to synthesise garnets which possess simultaneously a high MO figure of merit and large uniaxial magnetic anisotropy. However, the simultaneous optimization of several material properties and parameters can be difficult in single-layer garnet thin films, and it is also challenging to prepare films with high bismuth content using physical vapor deposition technologies. To meet the current challenge of developing next-generation functional MO materials, we design, develop and demonstrate the functionality of new magnetostatically-altered all-garnet multilayer heterostructures using two different garnet materials of dissimilar anisotropy types (out-of-plane and almost-in- plane). The multilayer structures possess simultaneously a high MO figure of merit and large uniaxial magnetic anisotropy together with low coercivity, if each of the layers is optimized in composition and annealed correctly. We prepare thin-film heterostructures by sandwiching a MO garnet layer with almost in-plane magnetization in-between two MO garnet layers with out-of-plane magnetization using RF sputtering. We apply customised high-temperature oven annealing processes (optimized in temperature and process durations after running many trials) for the as-deposited (amorphous) garnet multilayers to obtain the crystalline garnet phase in every layer. These structures then possess simultaneously a high optical/MO quality and low coercivity, which is very attractive for the development of magnetic photonic crystals, sensing devices and ultra-fast switches. Based on Bi-substituted ferrite garnets grown on garnet substrates, this new and unique method for the development of new magnetic materials, enables customized magnetic properties to be attained, and can be used to develop novel types of synthetic garnet materials.

Sn-DLC thin films were deposited by a dual magnetron sputtering system using a fixed DC power applied to a C target and a variable DC or HiPIMS power supply applied to a Sn target. Scanning electron microscopy (SEM) images showed the presence of larger Sn clusters on films deposited using HiPIMS compared with those deposited using DC power supply. The small resistivity of HiPIMS films can be related with the large Sn cluster and the elevated number of sp2 type bonding.

Zn x Cd 1-x S thin films at low zinc content have been deposited on bare soda lime glass substrates using RF magnetron co-sputtering of CdS and ZnS for the first time to investigate annealing effect on the structural and optical properties of the thin films. The as-deposited films were annealed in O 2 /N 2 ambient at annealing temperature ranging 200-500 °C. The composition of the films was controlled by varying RF power of CdS and ZnS in such a ratio so that zinc content in the thin films was low. The composition, structural, optical and surface morphological properties of the films was investigated using EDX, XRD, UV-Vis spectrophotometer and FESEM. The annealed films were observed hexagonal wurtzite structure with strong preferential orientation along (002) diffraction peak. Crystallinity of the films increased with increasing annealing temperature below 400 °C whereas beyond 400 °C new peaks were observed along with decreasing trend of (002) diffraction peak. Optical absorption and transmission spectra were recorded within the range 300-900 nm. With increasing annealing temperature, the band gap of the annealed films once decreased and then abruptly increased at around 400 °C. The decreased bandgap may have been due to possible increase in the crystalline nature of the material. From SEM, it was observed that the thin films were formed by different clusters of grains which later changed to isolated grains as the annealing temperature increased. This work confirms that annealing temperature has overbearing influence on the Zn x Cd 1-x S thin film properties deposited by RF magnetron co-sputtering.

ZnMgO films were prepared at room temperature on freestanding diamond (FSD) substrates by co-sputtering. The Mg content was controlled by varying RF sputtering power of MgO and the effects of Mg contents on the properties of ZnMgO films were investigated. The results showed that the (0002) peak of ZnMgO shifted from 34.5° to 35.6° with the increasing sputtering power of MgO target. The UV-visible and PL spetra of ZnMgO films revealed that the bandgap of ZnMgO was approximately linear related to the sputtering power of MgO target.

The amorphous HfO2 doped Gd2O3 (GDH) film has been grown on p-type Si (001) substrates by radio frequency co-sputtering, and the thickness of GDH film was 4.4nm. The results of electrical tests showed that the ΔVFB of C-V curves reduced from 170mV to 40mV, dielectric constant increased from 19.6 to 21.3, and relaxation phenomena decreased after RTA. I-V curves showed that the leakage current density of GDH film was reduced from 9.6×10-4 A/cm2 to 1.3×10-5 A/cm2 after Rapid Thermal Annealing (RTA). The reliability studies on GDH gate dielectric show that the Time Zero Dielectric Breakdown (TZDB) was mainly caused by the accumulation of positive charges.

Amorphous silicon oxycarbonitride (SiC x N y O z ) films have been deposited on Si substrates by low temperature reactive magnetron co-sputtering of silicon and graphite targets in mixed Ar/N 2 atmosphere. Our studies are focused on the influence of nitrogen incorporation on deposition rate, film composition, film structure, chemical bonds, and electrical resistivity of SiC x N y O z films investigated by profilometry, Rutherford Backscattering Spectrometry (RBS), X-ray diffraction (XRD), Raman spectroscopy, X-ray Photoelectron Spectroscopy (XPS), and four-point probe method. RBS results show that all samples contain significant amounts of oxygen (up to 16 at.%) which led to the formation of SiC x N y O z . Further, XPS results show that most of this oxygen is located in the film surface. With the addition of N 2 gas in the plasma, the carbon, and nitrogen contents in the films increase. The increased carbon content is due to the contribution of chemically driven sputtering of the graphite target and the reduction of the sputtering rate of the silicon target owing to poisoning by nitrogen. Raman spectra suggest that the films contain amorphous phases and that the a-C clusters suffer a graphitization with increased N 2 gas flow rate. The XRD analysis confirmed the amorphous structure of these films. According to the XPS analysis, the increase in nitrogen content leads to an increase in Si N and C N bonds, decreasing the Si C, Si Si, and C C bonds. Finally, the films electrical resistivity depends mainly on the nitrogen content, which makes it possible to obtain semiconductor or insulator SiC x N y O z films only by adjusting the N 2 concentration in the gas phase during the deposition process.

Doping of TiO 2 – a wide band gap material - with Neodymium (Nd 3+ ) ions have been the focus of research interest for the solar spectrum downshifting, a process which can improve the efficiency of silicon based solar cells. This work presents the influence of varying Nd doping concentration in the range 1.17-25 at.% in the TiO 2 host matrix. Thin films of thickness between 1 - 2 μm were deposited by Radio-Frequency Co-Sputtering of TiO 2 and Neodymium (Nd) target on quartz and silicon substrates at room temperature. The films are annealed in an air ambient after deposition. Film properties were studied from the structural and chemical composition point of view by means of X-ray diffraction (XRD), Auger Electron Spectroscopy (AES). Two distinct photoluminescence emission peaks were observed at 902 and 1080 nm in the doped films, pertaining to the transitions between the excited levels 4 F 3/2 to 4 I 9/2 and 4 I 11/2 levels of the Nd 3+ ions by exciting at 514.5 and 355 nm.

International audience; We report a study of the influence of the deposition conditions on the morphological parameters (shapes, size distribution and ordering) of Ag nanoclusters embedded in SiO(2), deposited by different techniques of co-sputtering or multilayer deposition. The influence of the substrate temperature on the nucleation and growth process is also studied. The different cluster morphologies determined by various complementary techniques (transmission electron microscopy, scanning electron microscopy, atomic force microscopy) are then correlated with the optical absorption, showing that the fabrication process is the key factor to control the position, shape and width of the surface plasmon resonance peaks and to achieve the desired optical properties. Films deposited by co-sputtering from 2 targets on a substrate heated at 440 degrees C show a very narrow absorption peak at 370 nm corresponding to the plasma resonance in near spherical silver particles. In multilayered films, the absorption peak is shifted from 340 to 480 nm with a larger half-band width. In cermet films co-sputtered from composite target on a rotating substrate, two absorption peaks are observed due to the more elongated shape of the metal nanoparticles. The experimental results are analysed in the frame of the Maxwell Garnett theory. (C) 2009 Elsevier B.V. All rights reserved.

7th International Conference on Electrical Transport and Optical Properties of Inhomogeneous Media (ETOPIM-7), Sydney, AUSTRALIA, JUL 09-13, 2006; International audience; Nano-structures are not an invention of the 20th century. In Middle Age already, craftsmen were able to produce multi-layer structures of nano-particles at the surface of potteries creating lustres, this means potteries with shining effects. In order to study the optical properties of these objects and because, as a part of our patrimony, they cannot be destroyed, we decided to reproduce the structures observed by co-sputtering. Developing a model, we were able to predict the reflection spectrum of the created samples with a good accuracy, validating it. However, this work is a first experimental step and improvements are needed from both theoretical and experimental sides in order to understand fully the optical properties of the lustres. (c) 2007 Elsevier B.V. All rights reserved.

We have deposited various FeAg granular systems having different iron content and we have investigated their giant magnetoresistive properties as a function of temperature. In a previous work we observed that, at room temperature, with increasing Fe content samples behaviour changes from superparamagnetic to ferromagnetic-like, and 20% is the concentration that separates these two regimes. In correspondence with this value, the dependence of giant magnetoresistance intensity as a function of iron concentration shows a maximum. With decreasing temperature, we observed that the position of this maximum shifts progressively towards lower iron concentrations. This behaviour has been discussed in terms of the presence of magnetic interparticle interactions. An analysis of the dependence of giant magnetoresistance as a function of applied field at the various temperatures is also presented.